1. Field of the Invention
The present invention relates generally to the field of gathering and storing video and range information to create an interactive visual representation known as virtuality, and more specifically to a method of using a camera and platform assembly for capturing pixels at an ordered series of locations defined by the three principle geometric axes and over a full 360 degree environment for storage in a computer memory for use with a virtual reality program, the assembly including a video or digital camera including a range finder to gather information for focusing and zooming the video tube or charge coupled device (CCD) prior to taking a video image and to gather range information, a positioning shaft on which the camera is mounted, a stepper motor for incrementally rotating the shaft and camera over 360 degrees, a linear actuator for moving the camera vertically along the positioning shaft, and a platform on wheels to which the shaft is attached for horizontally varying the camera position to capture all dimensions of objects within the environment and a computer on the platform for tracking and guiding the camera by controlling the stepper motor and for sensing camera location, linear actuator and operation of the platform wheels to move the platform to the next taping location, and for reconciling video information with the three principle axes defining space, and to a method of gathering video information including the steps of measuring the distance and location of each object in the environment from the camera with the range finder, capturing one horizontal resolution unit of visual information of the environment with the video camera, rotationally moving the positioning shaft and camera relative to the platform to capture the next horizontal resolution unit until a 360 degree rotation is complete, then moving the camera translationally along the positioning shaft to the level of the next vertical resolution unit and again capturing the 360 degrees of horizontal resolution units, or alternatively capturing all vertical EPE's and then moving to the next horizontal EPE, and thereafter moving the platform to a new location within the environment to begin capturing more environmental picture elements, until all required video information is stored. Several methods for capturing EPE's in different orders and with different hardware are provided, and these methods are not to be construed as limited by any particular hardware described herein. Several camera enhancing configurations of lenses and CCD's are also provided which are considered inventive in their own right, and also serve as examples of how the inventive methods may be performed.
2. Description of the Prior Art
There have long been cameras and camera mounting structures for capturing optical information for various purposes. These cameras and mounting structures have failed to provide a complete assembly that is well suited for gathering the optical information needed for generating virtual reality images.
One such prior device is that of Medina, U.S. Pat. No. 5,081,530, issued on Jan. 14, 1992. Medina discloses a camera and range finder assembly which can gather three-dimensional optical information about objects in its environment from a single location, using a precisely timed beam of energy. The reflected energy of the beam is detected by the camera, is separated by phase and is timed to measure distance and three-dimensional characteristics of objects. The information may be used for stereoscopic viewing or for machine operations. A problem with Medina, when applied to gathering optical information for virtualizing, is that neither a complete system nor method is presented for gathering and processing pixels from all sides of all objects in the environment.
Roberts, U.S. Pat. No. 5,138,459, issued on Aug. 11, 1992, teaches an electronic still video camera and personal computer combination for providing operator selectable digital compression, in a selectable format, recordable on a standard diskette. A problem with Roberts is that no range information is captured and Roberts is not panoramic. Another problem is that means of gathering optical information from an environment completely and methodically are not provided. While Roberts might form part of a virtual reality camera system, it is only a possible system element and not a system in itself.
Lucas, U.S. Pat. No. 5,111,289, issued on May 5, 1992, reveals a video camera and vehicle mounting structure, and a remote microphone and signal transmission mechanism. The camera is intended primarily for mounting inside the windshield of a police vehicle to tape images of speeding or erratically driven cars. The microphone would be carried on the policeman and the signals transmitted to and simultaneously recorded on the video tape. A problem with Lucas when applied to virtual reality taping is once again that no range information is captured and no provision is made for rapidly and panoramically receiving optical information. Thus, capturing a virtual environment using the Lucas device would likely be prohibitively time consuming.
Tuchiya, U.S. Pat. No. 5,068,735, issued on Nov. 26, 1991, discloses a system for controlling the tilting, panning and lifting of a panning head on which a television camera is mounted. Tuchiya further teaches servo-mechanisms for controlling focusing and zooming of the television camera, all under the guidance of a computer. A problem with Tuchiya is that no range information is captured and images are not processed and stored in a memory. Another problem is that no means is provided for substantially increasing information gathering speed, such as simultaneous taping in several directions at once. Another problem is that Tuchiya provides no means for automatically changing camera location for quickly taping objects in an environment from several perspectives, necessary for virtualizing.
Ishikawa, U.S. Pat. No. 5,040,016, issued on Aug. 13, 1991, reveals a camera and an external computer device mounted on the camera for providing additional camera functions. These functions might include automatic focusing or determination of an exposure mode. A problem with Ishikawa, if used for virtualizing, is that no range information is captured and no provision is made for rapid and accurate camera positioning. Another problem is that no provision is made for rapid gathering and storage of optical information in the multiple directions and positions necessary for complete capturing of an environment.
Jehle, U.S. Pat. No. 4,977,323, issued on Dec. 11, 1990, discloses a 360 degree infrared surveillance system for military vessel detection and identification. The system includes a scanning head rotated on a turntable having optical and infrared detectors in a vertical linear array, amplifiers for each detector and light emitting diodes (LED's) for each detector channel. The light from the LED's is imaged onto photo-detectors whose output is amplified and fed to a corresponding LED. An optical rotator causes the image of their light to rotate. Problems with Jehle include that no range information or true color images are captured, no provision is made for incremental camera elevation adjustments, camera position change within an environment or for accurate range finding, which are all important to virtualizing.
U.S. Pat. No. 5,113,253 may also be relevant, but is not available because it was withdrawn.
Pritchard, U.S. Pat. No. 5,014,126, issued on Oct. 23, 1989 relating to a single camera auto-stereoscopic imaging system is also considered relevant to complete disclosure.
It is thus an object of the present invention to provide a virtual reality camera and mounting structure assembly which can automatically capture imagery over 360 degrees at high speed and at incremental elevations, to make virtualizing practical.
It is another object of the present invention to provide such an assembly which is guided, tracked and coordinated by a computer.
It is still another object of the present invention to provide such an assembly which directs a laser range finder through the camera lens or another lens that targets the laser at the video target, for maximum accuracy and minimal optical distortion.
It is finally an object of the present invention to provide such an assembly which is relatively simple and reliable in design and inexpensive to manufacture.